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First shot at M31 - The Great Andromeda Galaxy


Gina
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A rare clear sky last night enabled my to capture M31 for the first time. 47 lights of 60s at ISO 800 and 4C (the lowest I could go after cooling system trouble - blown TEC needed replacing and I didn't have the right replacement - see cooling thread in DIY - Astromomer forum). 21 darks but no flats yet. Stacked in DSS using 37 lights and processed in PS. Scope was ED80 with 0.85x focal reducer.

post-13131-0-32314500-1340445361_thumb.p

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Well done for getting a shot at it Gina I took one shot of it before packing up last night while trying the Veil out all my subs were out of focus on that one so it will have to wait for another clear night, Must be more careful to check my focus after moving my scope.

I took one shot of M31 to see how it would fit in the evostars FOV but now I can see from your image how nicely it will come out. A good dark sky will really bring out those dust lanes for you. Good to see it again :grin:

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Nice one Gina, have not been able to see M31 yet, it's hanging over the town centre and the lights are killing it, maybe another few weeks :).

Jim

Thank you :) I was lucky - it missed the trees :) I have the LP problem with the Sagittarius region though.
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Well done for getting a shot at it Gina I took one shot of it before packing up last night while trying the Veil out all my subs were out of focus on that one so it will have to wait for another clear night, Must be more careful to check my focus after moving my scope.

I took one shot of M31 to see how it would fit in the evostars FOV but now I can see from your image how nicely it will come out. A good dark sky will really bring out those dust lanes for you. Good to see it again :grin:

Yes, it does fit rather well with the FR. When I checked its sie a while back it didn't all fit in but that was before the FR. That makes a big difference :) Funnily enough, I too forgot to check my focus before imaging M31 but fortunately it hadn't moved appreciably. And that was inspite of taking the camera off and putting it back.

Now I want that replacement TEC - I really miss the lower noise of the -15C temperature!

Edited by Gina
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Sorry to hear about the TEC but what a great start on M31, I'm planning on going to town on this object once it rises a bit higher, I hope I get as good a start as you have, congrats:)

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Very nice Andromeda GIna, should be my target for tonight as the real darkness not coming to later coincides with a nearly ideal position for me to shoot M31. May give witches broom a try if I get impatient though! Keeping fingers crossed for clouds to go away.

PS I think dropping your ISO from 1600 to 800 has given a better end result

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Sorry to hear about the TEC but what a great start on M31, I'm planning on going to town on this object once it rises a bit higher, I hope I get as good a start as you have, congrats:)

Thank you :)
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Looks good with the flats. Especially like the dust lane details!

Thank you :) I'm hoping to get more details next time I have a go at it. I really need the cooling properly fixed so that I can take longer exposures.
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Very nice Andromeda GIna, should be my target for tonight as the real darkness not coming to later coincides with a nearly ideal position for me to shoot M31. May give witches broom a try if I get impatient though! Keeping fingers crossed for clouds to go away.

PS I think dropping your ISO from 1600 to 800 has given a better end result

Thank you :) Hope the weather plays ball for you :) I'm hoping for clear skies tonight too to try the Broom, Veil and the rest of the Cygnus ring in wide-field. But I might decide to go for something else :D I needed to drop the ISO and keep the exposure low due to noise. ISO 1600 was OK with -15C but not at +4C.
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I've taken some bias frames to add in to the mix. I've also found the flats were taken at ISO 1600 instead of 800 so I've redone those too. I'm wondering if this was the cause of the vertical fringing. But I suspect that it might have been caused by using a TEC that takes nearly three times the current of the proper one.

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Gina,

The banding is mostly due to not exact calibration. Your darks should match more or less exactly the lights in temperature.

The ISO for flats does not really matter. Actually the lower the better.

Banding noise gets removed completely with Canon banding reduction script in PI

Mark

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Gina,

The banding is mostly due to not exact calibration. Your darks should match more or less exactly the lights in temperature.

The ISO for flats does not really matter. Actually the lower the better.

Banding noise gets removed completely with Canon banding reduction script in PI

Mark

Oh I see - thank you :) Currently I can't match flats and darks because the cooling isn't working so it's a matter of having the same ambient temperature. However, I can try on various night to see if I can match the EXIF T to the lights. I'll try that :)

I don't use PI ATM but thanks for the info :)

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I've taken new flats and also bias frames. I have set DSS to use 100% of supplied subs and not reject what it thinks are poorer. I found it was et to 80% so DSS was only ever using 80% of lights sent to it even after I had manually rejected any poor subs. I've now done a new stack with 44 lights of 60s at ISO 800 and 4C, 26 darks at same exposure (but slightly warmer), 25 flats, 33 bias and processed in PS. This is the result scaled to 1024px wide and saved as PNG:-

post-13131-0-82118200-1340558673_thumb.p

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Well, just come in for a coffee and am a happy bunny, on the offchance I turned the mount to M31 and there she is, at last my first sighting this year so will have to start getting the camera ready :). Experimenting with a couple of my webcams tonight I was able to get a glimps of it on the cam, a smudge but there she was :).

Jim

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